fix: 任务差额结算后 quota 和阿里视频时长优化 (#5923)

* fix: apply default ali video duration when value is non-positive

* fix: persist task quota after async settlement

model/task.go

@@ -417,6 +417,10 @@ func (Task *Task) Update() error {
 	return err
 }
 
+func (t *Task) UpdateQuota() error {
+	return DB.Model(t).Update("quota", t.Quota).Error
+}
+
 // UpdateWithStatus performs a conditional UPDATE guarded by fromStatus (CAS).
 // Returns (true, nil) if this caller won the update, (false, nil) if
 // another process already moved the task out of fromStatus.